Wind & Water is an independent guide to classical feng shui. It is not Feng Shui Architects Pty Ltd, the Sydney architecture practice that used this domain until the mid-2010s, and it has no connection to that firm, its principals or its teaching programmes.

The luopan: the feng shui compass, ring by ring

The luopan is a magnetic compass wrapped in an almanac. Every ring is a table of correspondences, printed in a circle.

A luopan is built from three parts: the needle in its well at the centre, a rotating disc called the heaven dial that carries the rings, and a square base plate crossed by two red threads. The practitioner squares the base with the building, turns the dial until the needle sits on its datum, and reads whichever rings the red threads cross.

The rings are the content. A small luopan may carry a handful; a full San He instrument carries dozens, and the classical San He layout is often taught as a core of thirteen. The essential ones repeat across almost every compass:

The Early Heaven and Later Heaven trigram rings, carrying the eight trigrams in their two arrangements.
The twenty-four mountains — the working ring, dividing the circle into twenty-four sectors of fifteen degrees, named from trigrams, heavenly stems and earthly branches. Direction readings in feng shui are quoted in these mountains.
The three plates: San He compasses famously carry the twenty-four mountains three times — the earth plate for reading sitting and facing, the human plate for reading mountains, and the heaven plate, shifted half a sector, for reading water. The three plates are the school's signature and the reason its luopan looks so dense.
Outer rings for the twenty-eight lunar mansions and fine degree divisions.

The two figures below survive from the study material the previous occupant of this domain published for a 1999 London conference paper on the San He luopan — they show the layout of a thirteen-ring instrument.

Reading one, in practice

The method is less mystical than the object. Establish the facing of the building. Read which of the twenty-four mountains it occupies. Then each ring answers a different question about that direction — which element it belongs to, which star governs it in the current cycle, which water paths suit it. The luopan does not tell a practitioner what to do; it is a lookup device, and the schools disagree about which rings matter, which is why each school's compass differs.